1. Field of the Invention
The present invention provides bacteria belonging to a new genus, and a process for production of carotenoids using a bacterium belonging to the new genus. The carotenoids of the present inventions are natural pigments useful for feed additives, food additives etc. Especially, astaxanthin is valuable in an industrial point of view as feed additives such as a color improver for bred fishes such as salmon, trout, red sea bream etc., and safe natural food additives. In addition, adonixanthin is, if its industrial production process is established, promising as food additives and feed additives as the astaxanthin is.
Further, .beta.-carotene has been used as food additives, feed additives, pharmaceuticals etc., echinenone is promised as food additives, feed additives etc.; canthaxanthin has been used food additives, feed additives, cosmetics etc.; and zeaxanthin has been used as food additives, feed additives etc.
2. Related Art
It is known that astaxanthin is contained in fishes such as red sea bream, salmon, trout, etc., and Crustacea such as shrimps, crabs, crawfishes, krills (Carotenoids of Marine Organisms; edt. Nippon Suisan Gakukai, 1978). As microorganisms which produce astaxanthin, red yeast Phaffia rhodozyma (Phytochemistry, 15, 1009, 1976), Brevibacterium (Journal of General and Applied Microbiology, 15, 127, 1969), and green algea Haematococcus pluvialis (Phytochemistry, 20, 2561, 1981) are known. As chemical synthetic processes, conversion of .beta.-carotene (Pure Appl. Chem. 57, 741, 1985) and synthesis from phosphonium salt (Helv. Chim. Acta. 64, 2436, 1981) are known.
However, the known process for production of astaxanthin are not advantageous due to high cost, because a content of astaxanthin in natural products such as krills, crawfishes, etc. is very low, and extraction thereof is difficult. In addition, stable availability of the resources is problematic. In addition, growth rate of red yeast, Phaffia rhodozvma, is low, productivity of astaxanthin by the red yeast is low, and extraction of astaxanthin is difficult since this yeast has hard cell wall. Therefore, industrial production of astaxanthin from the red yeast is difficult.
A growth rate of green algea, Haematococcus pluvialis, is also low, the culture is easily contaminated, and extraction of astaxanthin is difficult. Therefore industrial production of astaxanthin from the red algea is difficult.
It is known that adonixanthin is contained in goldfishes and carps (Carotenoids of Marine Organisms, Nippon Suisan Gakukai, 1978), but it is believed that chemical synthesis of adonixanthin is difficult. No industrial process for production of adonixanthin is known.
As production processes for .beta.-carotene, although synthesis from .beta.-Ionone (Pure & Appl. Chem. 63(1), 45, 1991), and extraction from green or yellow vegetables such as carrot, sweet potato, pumpkin etc. are known (Natural Coloring Agent Handbook, Korin (1979), edt. by editorial committee of Natural Coloring Agent Handbook), production cost of these processes is high. As processes for production of .beta.-carotene by microorganisms, the production by an algea Dunaliella (J. Appl. Bacteriol., 70, 181, 1991), and the production by a fungus Blakeslea (J. Appl. Bacteriol., 70, 181, 1991) are known. However, production of .beta.-carotene by bacteria is not known.
Echinenone is extracted from natural products, for example, starfishes such as crown-of-throns starfish, the internal organs of fishes such as red sea bream, sea urchin, the internal organs of Crustacea such as lobster, etc. (Carotenoids of Marine Organisms, edt. Nippon Suisan Gakukai, 1987). However, the production of echinenone by microorganisms is not known.
Canthaxanthin is known to be contained in a sort of mushrooms (Botanical Gazette, 112, 228-232, 1950), fishes, Crustacea etc. (Carotenoids of Marine Organisms, edt. Nippon Suisan Gakukai, 1978). The production of echinenone by microorganisms are exemplified by the production by microorganisms belonging to the genus Brevibacterium (Applied and Environmental Microbiology, 55(10), 2505, 1989), and by microorganisms belonging to the genus Rhodococcus (Japanese Unexamined Patent Publication No. 2-138996). In addition, as chemical synthetic processes, oxidation of .beta.-carotene (J. Amer. Chem. Soc., 78, 1427, 1956) and synthesis from novel compound 3-oxo-C.sub.15 phosphonium salt (Pure & Appl. Chem. 51, 875, 1979) are known.
As processes for production of zeaxanthin, a chemical synthesis starting from a hydroxy ketone obtained by asymmetric reduction of oxoisophorone (Pure & Appl. Chem., 63(1), 45, 1991), extraction from corn seeds (Seitai Shikiso, 1974, Asakura Shoten), and a process using Flavobacterium (Carotenoids, In Microbial Technology, 2nd edn. Vol. 1, 529-544, New York: Academic Press) are known.